I hope you realize that attempting to configure software not targetting OpenBSD is usually the domain of advanced users. Even on OpenBSD's official mailing lists, requests like this are usually outside of the scope of what is considered "normal" support. Sometimes porting is simple; most of the time, it is not.

Apparently, the Perl bindings installed through the RRDTool package were not understood by NfSen's Perl install script. This may be due to unrecognized code, but more than likely NfSen is a Linux-centric application. Given that Linux uses a different filesystem structure than OpenBSD, you may have a lot of work ahead of you to change the code into something that will work in the OpenBSD environment. I would suggest you begin by pinpointing what is errant in the above error message, followed by studying the compat_linux(8) & hier(7) manpages.

I have no knowledge of NfSen, so I cannot comment on the configuration files presented. Likewise, I make no guarantee that any of these comments will guide you to a successful port, but if I were you, I'd step back & search for alternatives already available on OpenBSD. I would highly recommend you search for "netflow" on the following sites:

I just got nfsen-1.3.2 up and running on 4.6 in the chroot apache, and it seems stable so far (everything is working, and i see no errors in any logs). If you still need help I could post some of my install details.

By checking the dates of the responses in this thread, you will see that this thread is six months old. The person claiming to have succeeded has not logged into this site since February, so I doubt anyone above will respond to your request.

However, all hope should not be lost, as NFSen was first committed to OpenBSD's ports tree just a few days ago:

Following the procedure described in Section 15 of the FAQ can be used for installation.

However, having been added to the ports tree within the last few days means that NFSen will not be available for OpenBSD 4.7-release or any older version of OpenBSD. 4.7-release will be available to the public between now & mid-May 2010. The code was finalized a few months ago, so the available NFSen port is only available today to -current users until the release of OpenBSD 4.8-release which is tentatively scheduled for November 2010.

If you are unsure about the differences between the -release & -current flavors of OpenBSD, study Section 5.1 of the FAQ.

I just got nfsen-1.3.2 up and running on 4.6 in the chroot apache, and it seems stable so far (everything is working, and i see no errors in any logs). If you still need help I could post some of my install details.